Differential capacitor devices such as differential MOSCAP devices are widely used in various applications and in various devices in the electronics industry. These semiconductor devices are fabricated using MOS, metal oxide semiconductor, manufacturing techniques, materials and principles. Differential capacitor devices include multiple capacitor sections or multiple capacitor plates or regions, and the different capacitor sections or different capacitor plates or regions can include different capacitances. Capacitance can be increased in one capacitor section of the MOS capacitor and decreased in another capacitor section of the MOS capacitor during operation, for example. Variable capacitances can be applied and the MOS capacitor devices therefore also serve as MOSVAR devices, i.e. MOS devices with variable reactance, i.e. variable capacitance.
MOSCAP devices are formed on or over semiconductor substrates using MOS processing operations. One problem that plagues differential capacitors is parasitic capacitance. Parasitic capacitance is present between electronic components or parts because of their proximity to each other. Parasitic capacitance can result between different capacitor electrodes coupled to different gates. Parasitic capacitance can also result between a capacitor electrode and the drain/source pickup devices used to couple various components such as a lower capacitor plate, to ground. Parasitic capacitance can alter the intrinsic capacitance of a capacitor and can also adversely affect the effective capacitance of the operating capacitor of the differential capacitor device. Parasitic capacitance negatively affects device speed and device performance.
It would therefore be desirable to provide methods and designs for differential MOS capacitor devices that eliminate or prevent parasitic capacitance.